Benzamide derivatives, anti-ulcer drug, and antibacterial drug

ABSTRACT

A benzamide derivative or a salt thereof expressed by the following formula 1: ##STR1## wherein R 1  is hydrogen atom or a lower alkyl group; R 2  is a benzyl or an alkenyl group; and 
     n is an integer of 1 to 6. 
     The benzamide derivative or a salt thereof has an anti-ulcer effect or an antibacterial activity against Hedicobacter pyroli, and has also high safety to be available for prevention or cure of ulcers.

RELATED APPLICATIONS

This application claims the priority of Japanese Patent Application No. 9-102632 filed on Apr. 4, 1997, which is incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a benzamide derivative and, in particular, to a benzamide derivative having an antibacterial activity against Helicobacter pyroli or an anti-ulcer effect.

BACKGROUND OF THE INVENTION

Various theories have been proposed with respect to a cause of ulcer in human. In particular, it has been elucidated that stress, taking of non-steroidal anti-inflammatory drugs for curing rheumatic diseases, and the like are closely related to ulcer formation, mainly due to relatively excess gastric or duodenal acid secretion. Accordingly, it is important to suppress the acid secretion in order to prevent ulcer formation and to cure it.

On the other hand, it has been considered that Helicobacter pyroli, which is a rod normally existing in stomach, generates ammonia due to its strong unease activity, thereby inducing ulcer. Since it persistently lives within mucus and mucosa, it becomes the greatest cause for recurrence of ulcer. Accordingly, it has been considered that the recurrence of ulcer can be prevented if this bacterium is sterilized.

Though various kinds of medicaments for curing ulcer have been conventionally developed, few medicaments have been known to have an effect for preventing stress ulcers from generating or an antibacterial activity against Helicobacter pyroli.

DISCLOSURE OF THE INVENTION

The present invention has been performed in view of the problems of the above-mentioned prior art and its object is to provide a compound which is excellent in preventing ulcer from generating and to provide antibacterial drug against Helicobacter pyroli and anti-ulcer drug including such a compound as a main component.

As a result of the diligent studies conducted by the inventors for the object, it has been found that a specific benzamide derivative is effective against various kinds of ulcer due to its antibacterial property against Helicobacter pyroli or its acid secretion inhibition as a main action mechanism. Thus, the present invention has been accomplished.

Namely, a benzamide derivative or a salt thereof in accordance with the present invention is expressed by the following formula 1: ##STR2## wherein R₁ is hydrogen atom or a lower alkyl group; R₂ is a benzyl or an alkenyl group; and

n is an integer of 1 to 6.

An anti-ulcer drug in accordance with the present invention comprises, as an effective ingredient, said benzamide derivative or the pharmacologically acceptable salt thereof, together with a pharmaceutically acceptable carrier and/or adjuvant.

An antibacterial drug against Helicobacter pyroli in accordance with the present invention comprises, as an effective ingredient, said benzamide derivative or the pharmacologically acceptable salt thereof, together with a pharmaceutically acceptable carrier and/or adjuvant.

A method for the treatment of peptic ulcers in man or mammals in accordance with the present invention comprises administering an effective amount of said benzamide derivative or the pharmacologically acceptable salt thereof to a host.

A method for the inhibition of acid secretion in stomach of man or mammals in accordance with the present invention comprises administering an effective amount of said benzamide derivative or the pharmacologically acceptable salt thereof to a host.

A method for the inhibition of growth of Helicobacter pyroli in stomach of man or mammals in accordance with the present invention comprises administering an effective amount of said benzamide derivative or the pharmacologically acceptable salt thereof to a host.

A method for the prevention of peptic ulcers in man or mammals in accordance with the present invention comprises administering an effective amount of said benzamide derivative or the pharmacologically acceptable salt thereof to a host.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an example of a step for manufacturing the benzamide derivative in accordance with the present invention and

FIGS. 2 to 6 show examples of steps for manufacturing material compounds for the benzamide derivative in accordance with the present invention.

EXAMPLES

In the compound of the present invention, the lower alkyl group found at R₁ is a straight or branched alkyl group having 1 to 6 carbon atoms. Examples thereof include methyl, ethyl, n-propyl, n-butyl, isopropyl, isobutyl, 1-methylpropyl, tert-butyl, n-pentyl, 1-ethylpropyl, isoamyl, and n-hexyl group. A preferable example of the lower alkyl group at R₁ is a branched alkyl group and, particularly, isobutyl group.

Though the benzyl group found at R₂ can be a benzyl group having no substituent, it is preferably a substituted benzyl group having at least one substituent. Preferable examples of the substituent include halogen atom such as fluorine, chlorine, bromine, or iodine. Particularly, fluorine atom is preferable.

The alkenyl group found at R₂ represents a straight or branched alkenyl group which has at least one double bond and has 2 to 20 carbon atoms. While the double bond has two kinds of configurations, namely, cis and trans, each double bond in alkenyl group may have either configurations. Among such alkenyl groups, a preferable example is a branched alkenyl group and, more preferably, prenyl, geranyl, neryl or farnesyl group. Particularly preferable example is geranyl group.

In the present invention, while n represents an integer of 1 to 6, it is preferable 3.

In the present invention, it is preferable that R₁, is an lower alkyl group and R₂ is a benzyl group. Further, it is preferable that R₁, is isobutyl group and R₂ is 4-fluorobenzyl group.

In the present invention, it is preferable that R₁, is hydrogen atom and R₂ is an alkenyl group. Further, it is preferable that R₂ is geranyl group.

In the following, while the general method for manufacturing the compound of the present invention will be explained, it should not be restricted thereto.

The compound(I) of the present invention expressed by formula 1 can be manufactured by reaction formula A shown in FIG. 1.

In reaction formula A, the benzamide derivative(I) of the present invention can be obtained from a carboxylic acid(II) and an amine(III) by using a known amide-bond forming reaction such as mixed anhydride method, acid chloride method, DCC method, CDI method, or azide method. Here, in reaction formula A, R₁, R₂ and n are defined as those of formula 1 mentioned above.

In the mixed anhydride method, by using an activator such as diphenyl phosphinic chloride, ethyl chloroformate, isobutyl chloroformate, or pivaloyl chloride, the carboxylic acid(II) is converted into its corresponding anhydride and then reacted with the amine(III). As an additive, for example, an organic base such as triethyl amine, pyridine, or N-methylmorpholine can be used. As a solvent, for example, a halogenated hydrocarbon such as dichloromethane or chloroform; an aromatic hydrocarbon such as benzene, toluene, or xylene; an ether such as tetrahydrofuran or dioxane; or an amide such as dimethylformamide or dimethylacetamide can be used. While the reaction temperature and reaction time may be changed according to the material compounds used, the reaction is usually effected at a temperature within the range of -15° C. to the reflux temperature of the solvent.

In the acid chloride method, as an activator, for example, phosphorus pentachloride, phosphorus trichloride, or thionyl chloride is used to convert the carboxylic acid (II) into the corresponding acid chloride and then the latter is reacted with the amine (III). As an additive, for example, an organic base such as triethyl amine, pyridine, or N-methylmorpholine can be used. As a solvent, for example, a halogenated hydrocarbon such as dichloromethane or chloroform; an aromatic hydrocarbon such as benzene, toluene, or xylene; or an amide such as dimethyl formamide or dimethylacetamide can be used. While the reaction temperature and reaction time may be changed according to the material compounds used, the reaction is usually effected at a temperature within the range of 0° C. to the reflux temperature of the solvent.

In the DCC method, as a condensing agent, for example, dicyclohexyl carbodiimde(DCC) or 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (WSCI) can be used. As a solvent, for example, a halogenated hydrocarbon such as dichloromethane or chloroform; an aromatic hydrocarbon such as benzene, toluene, or xylene; an ether such as tetrahydrofuran or dioxane; or an amide such as dimethylformamide or dimethylacetamide can be used. If necessary, this reaction may be effected while 1-hydroxybenzotriazole (HOBt) or N-hydroxy succinimide (HOSu) is added thereto. While the reaction temperature and reaction time may be changed according to the material compounds used, the reaction is usually effected at a temperature within the range of 0° C. to the reflux temperature of the solvent.

In the CDI method, as an activator, for example, N,N'-carbonyldiimidazole is used to convert the carboxylic acid (II) into the corresponding N-acyl derivative and then the latter is reacted with the amine(III). As an additive, for example, an organic base such as triethylamine, pyridine, or N-methylmorpholine or an inorganic base such as sodium hydride or potassium hydride can be used. As a solvent, for example, a halogenated hydrocarbon such as dichloromethane or chloroform; an aromatic hydrocarbon such as benzene, toluene, or xylene; an ether such as tetrahydrofuran or dioxane; or an amide such as dimethylformamide or dimethylacetamide can be used. While the reaction temperature and reaction time may be changed according to the material compounds used, the reaction is usually effected at a temperature within the range of 0° C. to the reflux temperature of the solvent.

In the azide method, as an activator, for example, diphenylphosphorylazide is used to convert the carboxylic acid (II) into the corresponding azide and then the latter is reacted with the amine (III). As an additive, for example, an organic base such as triethylamime, pyridine, or N-methylmorpholine is used. As a solvent, for example, a halogenated hydrocarbon such as dichloromethane or chloroform; an aromatic hydrocarbon such as benzene, toluene, or xylene; an ether such as tetrahydrofuran or dioxane; or an amide such as dimethylformanide or dimethylacetamide can be used. While the reaction temperature and reaction time may be changed according to the material compounds used, the reaction is usually effected at a temperature within the range of 0° C. to the reflux temperature of the solvent.

Specifically, for example, diphenylphosphinic chloride or pivaloyl chloride is used as an activator for the mixed anhydride method, while triethylamine is used as an additive to effect a reaction in a solvent such as chloroform or dimethyl formamide at a temperature within the range of -15° C. to room temperature, thereby attaining the aimed object.

While the material compound(II) used in reaction formula A can be synthesized by a known method, the material compound(II-a) in which R₂ is an alkenyl group can be synthesized by reaction formula B shown in FIG. 2, for example. In reaction formula B, R₁ and R₂ are defined as those of formula 1 mentioned above. Ra represents a carboxyl-protecting group which may be a lower alkyl group such as methyl group, ethyl group, or tert-butyl group, phenacyl group, or trichloroethyl group as long as no problem occurs in the subsequent reaction. X represents a halogen atom. In the following, Ra and X are similar to those above as long as there is no description.

In reaction formula B, an alkenyl halide(V) is reacted with a compound(IV) in the presence of a base and then hydrolyzed so as to synthesize the carboxylic acid (II-a).

The first step of this reaction can be effected in the presence of a base. Sodium amide, triethylamine, sodium hydride, sodium hydroxide, potassium carbonate, barium oxide, silver oxide, or the like can be used therefor. Also, a catalytic amount of potassium iodide can be added thereto. As a solvent, for example, an alcohol such as methanol, ethanol, or butanol; an aromatic compound such as benzene, toluene, xylene, or pyridine; an ether such as diethylether, tetrahydrofuran, or dioxane; an amide such as dimethylformamide or dimethylacetamide; or a ketone such as dimethylsulfoxide or acetone can be used. While the reaction temperature and reaction time may be changed according to the material compounds used, the reaction is usually effected at a temperature within the range of 0° C. to the reflux temperature of the solvent.

Specifically, for example, the compound (IV) is dissolved in tetrahydrofuran or N,N'-dimethylformamide and, after sodium hydride is added as a base and stirred therein, the alkenyl halide(V) is added thereto so as to effect a reaction at a temperature within the range of room temperature to the reflux temperature of the solvent, thereby attaining the aimed object.

In the reaction of the second step, the ester compound (VI) is hydrolyzed in the presence of an acid or a base so as to synthesize the carboxylic acid (II-a). Hydrochloric acid, sulfuric acid, p-toluenesulfonic acid, or the like can be used as the acid, while sodium hydroxide, potassium hydroxide, potassium t-butoxide, or the like can be used as a base. As a solvent, a carboxylic acid such as formic acid or acetic acid; an alcohol such as methanol or ethanol; water; or a mixed solvent thereof can be used. While the reaction temperature and reaction time can be changed according to the material compounds used, the reaction is usually effected at a temperature within the range of 0° C. to the reflux temperature of the solvent.

Specifically, for example, the ester compound(VI) is dissolved in an alcohol such as methanol or ethanol and then an aqueous sodium hydroxide or potassium hydroxide solution is added thereto so as to effect a reaction at a temperature within the range of room temperature to reflux temperature of the solvent, thereby attaining the aimed object.

The material compound (V) used in reaction formula B can be synthesized by reaction formula C shown in FIG. 3, for example. In reaction formula C, R₂ and X are defined as those of reaction formula B mentioned above.

In this reaction, an alkenyl halide (V) can be obtained by halogenation of alcohol (VII).

For this reaction, a general method known as halogenation of hydroxy groups can be used. As a reagent of halogenation, for example, a strong acid such as hydrochloric acid or hydrochloric acid; a phosphorus compound such as phosphorus tribromide, phosphorus trichloride, or phosphorus pentachloride; thionyl chloride; N-halogenosuccinimide and dimethyl sulfide; triphenylphosphine and a halogenated hydrocarbon; or methanesulfonyl chloride and lithium halide is used to effect the reaction. As a solvent, for example, a halogenated hydrocarbon such as dichloromethane or chloroform; an aromatic compound such as benzene, toluene, xylene, or pyridine; an ether such as diethylether, tetrahydrofuran or dioxane; or an amide such as N,N-dimethylformamide or N,N-dimethylacetamide can be used. While the reaction temperature and reaction time may be changed according to the material compounds used, the reaction is usually effected at a temperature within the range of 0° C. to the reflux temperature of the solvent.

Specifically, for example, in the presence of lithium chloride and triethylamine, methanesulfonyl chloride is used so as to effect a reaction in a solvent such as acetone at a temperature within the range of 0° C. to room temperature, thereby attaining the aimed object.

On the other hand, the material compounds(II-b) in which R₁ is a lower alkyl group and R₂ is a benzyl group in the material compound (II), can be synthesized according to reaction formula D shown in FIG. 4, for example. In reaction formula D, R₁ is defined as that of formula 1 mentioned above. R₃ represents hydrogen or halogen atom.

At the first step of reaction formula D, the compound (VIII) is reacted with the benzyl halide(IX) in the presence of a base so as to obtain the compound (X). As a base in this reaction, for example, an inorganic base such as potassium carbonate, potassium hydroxide, sodium hydroxide, or sodium hydride; or an organic base such as triethylamine or pyridine can be used. Specifically, for example, potassium carbonate is used as a base so as to effect a reaction in a solvent such as acetone or N,N-dimethylformamide at a temperature within the range of room temperature to the reflux temperature of the solvent, thereby attaining the aimed object.

At the second step of reaction formula D, the compound(X) is hydrolyzed so as to obtain the carboxylic acid(II-b). This reaction can be effected under the condition similar to that of the second step in reaction formula B.

The material compound(VIII) used in reaction formula D may be commercially available or easily synthesized by using a known method. For example, the compound (VIII-a) can be manufactured according to reaction formula E shown in FIG. 5. In reaction formula E, each of Z₁, Z₂, Z₃, Z₄, and Z₅ represents hydrogen atom or a lower alkyl group.

At the first step of reaction formula E, the compound(XI) is reacted with the alkenyl halide (XII) in the presence of a base so as to obtain the compound (XIII). As a base in this reaction, for example, an inorganic base such as potassium carbonate, potassium hydroxide, sodium hydroxide, or sodium hydride, or an organic base such as triethylamine or pyridine can be used. Specifically, for example, potassium carbonate is used as a base so as to effect a reaction in a solvent such as acetone or N,N-dimethylformamide at a temperature within the range of room temperature to the reflux temperature of the solvent, thereby attaining the aimed object.

At the second step of reaction formula E, the compound(XIII) is subjected to Claisen rearangement reaction so as to obtain the compound(XIV). This reaction is effected in or without the presence of a high-boiling solvent under normal or high pressure. Examples of the high-boiling solvent include phenyl ether and N,N-dimethylaniline. While the reaction temperature and reaction time may be changed according to the material compounds used, the reaction is normally effected at a temperature within the range of 100° to 200° C.

At the third step of reaction formula E, the compound(VIII-a) can be obtained by hydrogenation of the compound (XIV). When this reaction is effected under a catalytic reduction condition, as a catalyst, palladium, platinum, nickel, rhodium, ruthenium, or the like can be used. Specifically, for example, by using palladium-carbon, in a solvent such as ethanol, ethyl acetate, or tetrahydrofuran, under a hydrogen gas atmosphere, a reaction is effected at a temperature within the range of room temperature to the reflux temperature of the solvent, thereby attaining the aimed object.

On the other hand, the material compound (III) used in reaction formula A can be synthesized according to reaction formula F shown in FIG. 6. In reaction formula F, n is defined as that of formula 1 mentioned above.

At the first step of reaction formula F, from an aldehyde (XV) and piperidine (XVI), the compound (XVII) can be synthesized. Specifically, for example, the aldehyde(XV) is dissolved in a solvent such as ethanol and then the solution, with piperidine (XVI) and sodium borohydride added thereto, is stirred at room temperature, thereby attaining the aimed object.

The alkylation at the second step of reaction formula F can be effected by a normal method. Specifically, to the solution of the compound (XVII) in a non-polar solvent such as toluene is added a base such as sodium hydroxide, and then the mixture, with the compound(XVIII) added thereto, is refluxed, thereby synthesizing the compound (XIX).

The deacylation at the third step of reaction formula F can be effected by a normal hydrolysis to synthesize the amine(III). Specifically, a reaction of the solution of the compound (XIX) in sulfuric acid is effected at the reflux temperature, thereby attaining the aimed object.

Among the material compounds used in the above-mentioned reaction formulas, those with no preparation methods described may be commercially available or easily synthesized by using a known method.

Also, examples of salts of the benzamide derivative(I) of the present invention with an acid include salts with inorganic acids such as hydrochloric acid, hydrobromic acid, sulfuric acid, or phosphoric acid and salts with organic acids such as acetic acid, propionic acid, citric acid, lactic acid, oxalic acid, maleic acid, fumaric acid, succinic acid, tartaric acid, or methane sulfonic add. These salts can be easily manufactured by a normal method.

The benzamide derivative in accordance with the present invention has a strong effect against stress ulcer and an excellent effect for suppressing gastric acid secretion. Further, it has an antibacterial activity against Helicobacter pyroli which is supposed to be a cause for recurrence of ulcer. Furthermore, it has a high safety. Accordingly, it is useful as a medicament for curing and preventing peptic ulcer in man or mammals and, particularly, gastric ulcer in man Conventionally, there has hardly been known such a compound which has both effect for suppressing gastric acid secretion and antibacterial activity against Helicobacter pyroli. Accordingly, it is indicated that the compound of the present invention is not only effective in preventing and curing ulcer but also in preventing the recurrence thereof.

When the compound of the present invention is administered as a medicament for curing and preventing peptic ulcer, it may be administered orally as tablet, powder, granule, capsule, syrup, or the like as well as parenterally as suppository, injection, external drug, instillation or the like. While the amount of administration may be outside of the range mentioned below according to the degree of symptom, personal difference, age, kind of ulcer, or the like, it should of course be adjusted so as to fit the individual circumstances in specific cases. Usually 0.01 to 200 mg/kg or, preferably, 0.05 to 50 mg/kg or, more preferably, 0.1 to 10 mg/g is administered per day for an adult in a single dose or several doses.

When formulating the medicament, a normal manufacturing method is used with a normal formulation carrier. If necessary, pharmacologically and pharmaceutically acceptable additives may be added thereto.

Namely, when preparing an oral solid formulation, after an excipient and, if necessary, a binder, a decaying agent, a luster, a coloring agent, a correctives, and the like are added to the main medicament, a normal method is used to form tablet, coated tablet, granule, powder, capsule, or the like.

Examples of the excipient include lactose, corn starch, sucrose, glucose, sorbitol, crystalline cellulose, and silicon dioxide. Examples of the binder include polyvinylalcohol, polyvinylether, ethyl cellulose, methyl cellulose, gum arabic, tragacanth, gelatin, shellac, hydroxypropyl cellulose, hydroxypropyl starch, and polyvinylpyrrolidone. Examples of the decaying agent include starch, agar, gelatin powder, crystalline cellulose, calcium carbonate, sodium hydrogencarbonate, calcium citrate, dextrin, and pectin. Examples of the luster include magnesium stearate, talc, polyethyleneglycol, silica, and hardened vegetable oil. As the coloring agent, those permitted to be added to medicines are used. Examples of the correctives include cocoa powder, menthol, aromatic acid, mentha oil, borneol, and cinnamon powder. If necessary, these tablet and granule can be coated with sugar-coating, gelatin-coating, and the like.

When preparing an injection, if necessary, a pH-adjusting agent, a buffer, a stabilizer, a solubilizer, and the like are added to the main medicament and then a normal method is used to form subcutaneous, intramuscular, and intravenous injection drugs.

In the following, the present invention will be explained in further detail by specifically examples. However, the present invention should not be restricted to these examples.

First, test methods used for evaluating these examples will be explained.

WIS: Restraint and Water Immersion Stress-Induced Ulcer Inhibition Test

i)Meaning

The degree of inhibition of the stress ulcer formation is tested.

ii)Method

Male Crj:SD or Slc:SD rats (6 to 7-week-old) were fasted overnight, but allowed free access to water. Each group has 5 to 8 of these rats. The sample compound was dissolved or suspended in an aqueous solution of 0.3% sodium carboxymethylcellulose or 0.05% Tween 80 and then was orally administered (100 mg/10 ml/kg). To a control group, the vehicle was administered. 10 minutes later, the rats were placed in a stress cage and immersed to the level of xipfoid process in a water bath (21° C.) for 7 hours. At the end of the stress, the rats were sacrificed by inhalation of ether or carbon dioxide. Then, the stomach of each was removed, inflated by injecting 10 ml of 5% formalin neutral buffer solution, and immersed in 1% formalin neutral buffer solution for 30 minutes or more to be fixed. The stomach was incised along the greater curvature and then the length of each erosion in the glandular portion was determined under dissecting microscope. The sum of the length of erosions per stomach was defined as ulcer index (UI).

iii)Judgment Standard

The effect obtained when 100 mg/kg of the sample compound had been administered was expressed as ulcer formation inhibitory rate (%) as follows:

    ulcer formation inhibitory rate (%)=(1-(UI in sample group/UI in control group))×100

CAP: Acid Secretion Inhibition Test In Vitro

i)Meaning

The acid secretion inhibitory activity in a cell level is studied. It can also be used for studying the mechanism of the effect.

ii)Method

ii-a) Preparation of isolated gastric fundus gland suspension

First, an isolated gastric fundic gland sample was prepared. Namely, a male Japanese White rabbit (2.5 to 3 kg) was anesthetized to death with Nembutal™ and then the abdomen was incised. Immediately thereafter, the stomach was removed and, after its pyloric and cardiac antrum were severed, incised along its greater curvature into two sheets. The gastric contents adhering to the mucosal surface was washed out with ice-cooled PBS (-) and then carefully washed therein. The gastric wall was spread on a cork board with its mucosal surface facing up and the feed and mucus thereon were completely removed with sterile gauze. The mucosa was separated therefrom by a spatula and then collected in ice-cooled PBS (-). After being washed twice with PBS (-), the mucosa was minced into 2-3 mm³ pieces by scissors. These pieces were further washed twice with a nutrient solution. The nutrient solution comprises 132.4 mM of NaCl, 5.4 mM of KCl, 5 mM of Na_(z) HPO₄. 12H₂ O, 1 mM of NaH₂ PO₄.2H₂ O, 1.2 mM of MgSO₄, 1 mM of CaCl₂, 25 mM of HEPES, 2 mg/ml of glucose, and 1 mg/ml of BSA.

Into 70 ml of the nutrient solution containing 1 mg/ml of collagenase, minced mucosal pieces were dispersed and intensely stirred in a conical flask with a stirrer at 37° C. for 40 to 60 minutes. During this period, 100% O₂ was sprayed on the nutrient solution surface and the pH was appropriately measured such that it was immediately adjusted to pH 7.4, when the value was therebelow, with a base. The nutrient solution was added to the reaction solution so as to attain the total amount of about 200 ml. After being filtered through a mesh, the suspension was divisionally introduced into 50 ml centrifuge tubes and left for 15 minutes such that gastric fundic gland was deposited. The supernatant was repeatedly removed by an aspirator, dispersed in the nutrient solution, and then left such that the gastric fundic gland was washed three times. At this time, without using a pipette, the suspension was alternately introduced into two centrifuge tubes so as to effect dispersion. The number of cells was counted under microscope and adjusted to 1.6×10₆ cells/ml.

ii-b) ¹⁴ C!-aminopyrine uptake test

Then, ¹⁴ C!-aminopyrine uptake test was performed. After an Eppendorf tube was weighed, 10 μl (final concentration: 10⁻⁵ M) of histamine dissolved in the above-mentioned nutrient solution, 10 μl (final concentration: 10⁻⁵ M) of the test compound dissolved in DMSO, and 10 μl (final concentration: 0.05 μCi/ml) of ¹⁴ C!-aminopyrine diluted with the nutrient solution were introduced therein and then 970 μl of the isolated gastric fundic gland suspension prepared above was added thereto. Subsequently, this mixture was shaken at 37° C. for 40 minutes at 125 cycles/minute. After being centrifuged for 30 seconds, 200 μl of its supernatant was collected into a mini-vial, while the rest was removed by an aspirator. The gland pellet was completely dried as the tube with its lid being opened was kept for one night in a drying oven at 80° C. and then the lid was closed and the weight was determined at room temperature. Then 100 μl of 1N KOH was added thereto and the tube with its lid being closed was treated at 60° C. for 1 to 2 hours so as to dissolve the pellet. Then, the contents thereof were transferred to a mini-vial. Into the mini-vial containing the supernatant or gland pellet, 4 ml of Atomlite™ was added and then the radioactivity was measured by a liquid scintillation counter. Here, after the radioactivity of the gland pellet was corrected by using a sample in which 20 mM of NaSCN was added so as to cancel the hydrogen ion concentration gradient, the integration ratio of aminopyrine specifically trapped by the gland pellet was calculated. This experiment was performed in duplicate.

ii-c) Calculation of the accumulation rate of aminopyrine

Here, its principle will be briefly explained. In the isolated gastric fundic gland, acid is accumulated in a space between its secretory tubule and intraglandular cavity. Aminopyrine is weak base (pKa=5.0) and nonionic in a neutral solution so as to freely pass through the cell membrane, whereas it is ionized in an acidic solution and thus cannot pass through the cell membrane due to its electric charge. Therefore, aminopyrine is accumulated in a closed acidic space within the isolated gastric fundic gland. In view of this characteristic, the accumulation rate (R) of aminopyrine is calculated by the following equation:

    R=((corrected radioactivity of precipitate)/(radioactivity of supernatant))×(200/(mg dry weight of gland pellet))

iii)Judgment Standard

The effect of the sample compound at the final concentration of 10⁻⁵ M was expressed by acid secretion inhibitory rate (%) as follows:

    acid secretion inhibitory rate (%)=(1-(R in sample group/R in control group))×100

AHP: Antibacterial Activity Test Against Helicobacter pyroli

i)Meaning

The minimum inhibitory concentration (MIC) against Helicobacter pyroli (microaerophilic gram-negative bacterium which is supposed to deeply involve in pathogenesis, relapse, and recrudescence of ulcer, referred to as "HP" in the following) is measured so as to find out compounds which have antibacterial activity against Helicobacter pyroli.

ii)Method

MICs were determined by the agar dilution method. The stock culture (-80° C.) of HP NCTC 11637 was thawed and cultured on tripticase soy agar supplemented with 5% sheep blood at 37° C. in an atmosphere of 5% O₂, 10% CO₂, and 85% N₂. Grown colonies were transferred to the same plate and precultured for 3 days under the same condition.

A 1,000 μg/ml solution of the sample compound containing DMSO not more than 25% was diluted with sterile purified water so as to have various kind of concentrations. 100 μl volume from each dilution was mixed thoroughly with 900 μl of brucella agar supplemented with 5% horse blood and solidified in a 24 well micro plate, thereby yielding an MIC measurement plate.

An appropriate amount of the colony grown on the plate by preculturing was suspended in Mueller Hinton broth till turbidness was recognizable by naked eyes, thereby yielding a bacterial suspension concentrate containing about 107 cfu/ml. This bacterial suspension concentrate was diluted 100-fold in the same broth; this resulted in a bacterial suspension for inoculation containing about 10⁵ cfu/ml of the bacteria.

10 μg l of the bacterial suspension for inoculation (about 10³ cfu) was dropped by dispenser onto an MIC plate for inoculation and cultured for 7 days under the same condition as that of preculture. Thereafter, it was judged whether there had been bacteria growth or not.

iii)Judgment Standard

The minimum concentration of the sample compound when there were no visible colonies or, if any, 5 or less colonies of HP was defined as MIC (μg/ml).

MTT: Cell Damaging and Protecting Effect Test

i)Meaning

It is confirmed that there is no toxicity in cell level. Those having a toxicity in cell level are inappropriate as an anti-ulcer drug. Also, it can be confirmed that the effects of the sample compounds in other cell level tests do not result from their toxicity.

ii)Method

A male Japanese White rabbit (2.5 to 3 kg) was anesthetized to death by Nembutal™ and, immediately thereafter, its stomach was removed. The greater curvature of the stomach was incised so as to remove the stomach contents therefrom. After the mucosal surface was washed with HBSS (Hanks' Balanced Salt Solution), the stomach in ice-cooled HBSS was transferred to a laboratory. Then, after the pyloric antrum was removed, the gastric corpus mucosa was separated by a spatula and then minced into 2 to 3 mm³ pieces in BME (Basal Medium Eagle). Thereafter, these pieces were shaken at 120 to 130 cycles/minute for 15 minutes at 37° C. in BME 60 ml containing 280 U/ml of dispase and 30 to 50 U/ml of collagenase. Here, the concentration of collagenase was appropriately changed for each lot in view of the state of cells. The pieces were washed twice with EBSS (Earle's Balanced Salt Solution) containing 1 mM of EDTA and then shaken in MEM (Minimum Essential Medium) containing 1 mM of EDTA at 37° C. for 5 minutes. Subsequently, they were shaken in the dispase and collagenase having the same concentrations as those mentioned above for 15 minutes so as to remove the supernatant and then further shaken at 37° C. for 50 to 60 minutes at 120 to 130 cycles/minute. Then, after being washed twice with HBSS, Ham F12 containing 2% of Ultrocer G™ was used to attain the concentration of 1×10⁶ cells/ml. Thus formed suspension was dispensed in each well of a 96-well plate by 200 μl. The plate was incubated in the atmosphere composed of 5% CO₂ and 95% air at 37° C. for three days so as to attain a confluent state and then subjected to MTT assay.

The sample compound was dissolved in DMSO so as to attain a concentration of 10⁻² M and then diluted with HBSS containing 2% of Ultrocer G™ so as to attain a final concentration of 10⁻⁴ M. To each group, which 8 wells were used for, 10 μl of MTT reagent was added immediately after 100 μl of the medium in each well was exchanged for same volume of the resulting solution of the sample compound. After being incubated in an atmosphere composed of 5% CO₂ and 95% air at 37° C. for 4 hours, thus formed solution was centrifuged and then its supernatant was discarded. Subsequently, 100 μl of 100% ethanol was added to the residue so as to dissolve MTT formazan. Then, the absorbance (OD: 570 to 630) was measured by a microplate reader. This method utilizes a phenomenon in which MTT is changed to MTT formazan only by mitochondria of living cells so as to change color.

iii)Judgment Standard

The cell damaging or cell protecting effect of the sample compound at the final concentration of 10₋₄ M was expressed as cell damaging rate (%) as follows:

    cell damaging rate (%)=(1-(absorbance in sample group/absorbance in control group))×100

Accordingly, the smaller value is better in the cell damaging rate.

Based on the foregoing effect tests and safety test, the following compounds were tested.

EXAMPLE 1 ##STR3## EXAMPLE 2 ##STR4##

                  TABLE 1     ______________________________________     Example  Anti-ulcer Tests                          Anti-HP Test                                     Test for Safety     No.      WIS     CAP     AHP      MTT     ______________________________________     1        55      104.0   3.13˜12.5                                       -3     2        62      102.5            49     ______________________________________

As clearly from Table 1, a compound of this compound group 1 has an excellent anti-ulcer effect, acid secretion inhibition effect and high antibacterial activity against Helicobacter pyroli. Also, it can be understood that they have high safety.

In the following, the manufacturing method of Examples of the present invention will be explained.

At first, the synthetic methods of the material compounds used for synthesizing Examples of the present invention will be shown as Reference Examples 1 to 3.

REFERENCE EXAMPLE 1

Synthesis of 4-geranyloxybenzoic acid

To a solution of methyl 4-hydroxybenzoate (7.61 g) in acetone(80 ml) were added geranyl bromide (10.9 g) and potassium carbonate (13.8 g), and then the mixture was refluxed with heating for 6 hours. After the reaction, water (150 ml) was added to the reaction mixture, and the mixture was extracted with chloroform The organic layer was dried over sodium sulfate anhydride and then concentrated under a vacuum. The residue was purified by silica gel column chromatography (hexane:ethyl acetate=9:1), thereby yielding 13.00 g of methyl 4-geranyloxy benzoate.

To a solution of methyl 4-geranyloxybenzoate(13.00 g) in methanol(50 ml) was added aqueous solution(10 ml) of potassium hydroxide (3.90 g). After being stirred overnight at room temperature, the mixture was refluxed with heating for 1 hour. After being acidified with concentrated hydrochloric acid, the reaction mixture was extracted with chloroform. The organic layer was dried over sodium sulfate anhydride and then the solvent was evaporated out under a vacuum. The resulting solid was recrystallized from hexane/ethyl acetate mixed solution, thereby yielding 9.77 g(71%) of the aimed compound.

REFERENCE EXAMPLE 2

Synthesis of ethyl 4-hydroxy-3-isobutylbenzoate

Ethyl 4-hydroxy-3-methallylbenzoate (25.5 g) was dissolved in ethanol (250 ml) and then, with 10% palladium charcoal (2.6 g) added thereto, this mixture was stirred at room temperature for 41 hours under a hydrogen gas atmosphere. After the reaction mixture was filtered, the filtrate was concentrated under a vacuum, thereby yielding 25.6 g of the aimed oily compound.

REFERENCE EXAMPLE 3

Synthesis of 4-(4-fluorobenzyloxy)-3-isobutylbenzoic acid

Ethyl 4-hydroxy-3-isobutylbenzoate (25.6 g), potassium carbonate (31.8 g), and 4-fluorobenzyl bromide (26.1 g) were refluxed in acetone (150 ml) with stirring for 4 hours. The reaction mixture, with water added thereto, was extracted with ethyl acetate. The extract was concentrated under a vacuum. The resulting residue, with water (50 ml), potassium hydroxide (12.9 g), and ethanol (100 ml) added thereto, was refluxed with stirring for 2 hours. The reaction mixture, with water added thereto, was neutralized with hydrochloric acid and then extracted with ethyl acetate. The extract was washed with 10% hydrochloric acid and water successively, dried over sodium sulfate anhydride, and then concentrated under a vacuum. Thus obtained solid was recrystallized (from n-hexane/ethanol), thereby yielding 30.8 g of the aimed compound.

EXAMPLE 1

4-(4-fluorobenzyloxy)-3-isobutylbenzoic acid(1.42 g) was dissolved in chloroform (50 ml) and triethylamine (1.30 ml), and then diphenylphosphinic chloride (0.90 ml) was added thereto while being cooled with ice. After being stirred for 1 hour, the mixture, with 3- 3-(piperidinomethyl)phenoxy!propylamine(1.17 g) added thereto, was stirred for 15 hours at room temperature. The reaction mixture was washed with saturated sodium hydrogencarbonate aqueous solution and saturated brine successively, dried over sodium sulfate anhydride, and then concentrated under a vacuum The residue was purified by silica gel column chromatography (chloroform:methanol=20:1), thereby yielding an amide(2.71 g).

To the solution of this amide in diethylether(50 ml) was added 1N hydrochloric acid ether solution (10 ml) was added. After stirring for 5 minutes, the crystals deposited were filtrated, thereby 2.62 g(98%) of the aimed compound.

m.p. 73.8°-75.8° C.; ¹ H-NMR (CDCl₃)δ: 11.95(1H, s), 7.86-7.48(3H, m), 738(2H, d, J=8.3 Hz), 7.07(2H, d, J=8.3 Hz), 7.05-6.86(4H, m), 5.06(2H, s), 4.30-3.90(4H, m), 3.74-3.30(4H, m), 3.15-2.47((3H, m), 2.55(2H, d, J=6.8 Hz), 2.38-2.05(4H, M), 2.01-1.30(5H, m), 0.89(6H, d, J=6.8 Hz).

EXAMPLE 2

4-geranyloxybenzoic acid(1.50 g) was dissolved in chloroform (100 ml) and triethylamine (1.52 ml), and then diphenylphosphinic chloride (1.04 ml) was added thereto while being cooled with ice. After being stirred for 1 hour, the mixture, with 3- 3-(piperidinomethyl)phenoxy!propylamine(1.49 g) added thereto, was stirred for one night at room temperature. The reaction mixture was washed with saturated sodium hydrogencarbonate aqueous solution and saturated brine successively, dried over sodium sulfate anhydride, and then concentrated under a vacuum The resulting solid was recrystallized from ethyl acetate/n-hexane, thereby 2.07 g of the aimed compound.

m.p. 74.7°-75.6° C.; ¹ H-NMR (CDCl₃)δ: 7.73(2H, d, J=8.6 Hz), 720(1H, t, J=7.9 Hz), 6.98-6.86(4H, m), 6.83-6.76(1H, m), 6.58(1H, m), 5.48(1H, t, J=6.4 Hz), 5.14-5.05(1H, m), 4.58(2H, d, J=6.4 Hz), 4.12(2H, t, J=6.4 Hz), 3.57(2H, q, J=4.9 Hz), 3.43(2H, s), 2.37(4H, m), 2.19-2.02(6H, m), 1.74(3H, s), 1.68(3H, s), 1.66-1.49(7H, m), 1.49-1.35(2H, m). 

What is claimed is:
 1. A benzamide compound or a salt thereof expressed by the following formula 1: ##STR5## wherein R₁ is hydrogen atom or a lower alkyl group; R₂ is a benzyl or an alkenyl group; andn is an integer of 1 to
 6. 2. A benzamide compound or a salt thereof according to claim 1, wherein n is
 3. 3. A benzamide compound or a salt thereof according to claim 1, wherein R₁ is a lower alkyl group and R₂ is benzyl group.
 4. A benzanide compound or a salt thereof according to claim 3, wherein R₁ is isobutyl group and R₂ is 4-fluorobenzyl group.
 5. A benzamide compound or a salt thereof according to claim 1, wherein R₁ is hydrogen atom and R₂ is an alkenyl group.
 6. A benzamide compound or a salt thereof according to claim 5, wherein R₂ is geranyl group.
 7. A pharmaceutical composition as an anti-ulcer drug comprising, as an effective ingredient, a benzamide compound or a pharmacologically acceptable salt thereof according to claim 1, together with a pharmaceutically acceptable carrier and/or adjuvant.
 8. A Pharmaceutical composition as an antibacterial drug against Helicobacter pyroli comprising, as an effective ingredient, a benzamide compound or a pharmacologically acceptable salt thereof according to claim 1, together with a pharmaceutically acceptable carrier and/or adjuvant.
 9. A method for the treatment of peptic ulcers in man or mammals, which comprises administering an effective amount of a benzamide compound or a pharmacologically acceptable salt thereof according to claim 1 to a host.
 10. A method according to claim 9, wherein said peptic ulcers are gastric ulcers in man.
 11. A method for the inhibition of acid secretion in stomach of man or mammals, which comprises administering an effective amount of a benzamide compound or a pharmacologically acceptable salt thereof according to claim 1 to a host.
 12. A method for the inhibition of growth of Helicobacter Pyroli in stomach of man or mammals, which comprises administering an effective amount of a benzamide compound or a pharmacologically acceptable salt thereof according to claim 1 to a host.
 13. A method for the prevention of peptic ulcers in man or mammals, which comprises administering an effective amount of a benzamide compound or a pharmacologically acceptable salt thereof according to claim 1 to a host.
 14. A method according to claim 13, wherein said peptic ulcers are gastric ulcers in man. 